The present invention relates to a recording apparatus including a laser modulation device which can modulate the output of a laser at three levels or more.
A recording apparatus in which a recording photosensitive member is optically scanned using a laser beam so as to record data from an external circuit thereon is known as a device using a laser modulation device of this type. In this apparatus, the intensity of a laser beam is modulated at, e.g., three levels so as to perform printing in black, white, and halftone on printing paper.
In this recording apparatus, in order to maintain printing quality, the intensity of a laser beam must be constant. However, since a semiconductor laser is greatly influenced by temperature, a laser output thereof is greatly changed by a slight change in temperature and it is difficult to stabilize a laser output. Furthermore, when laser modulation is performed at multiple levels, e.g., three levels or more, the intensity of the laser beam must be stabilized in each level.